Environmental smoke exposure (involuntary smoke exposure) has been incriminated as a contributor to the increased lung cancer incidence in the U.S.A. and other developed countries. Epidemiological studies have also indicated associations for involuntary smoke exposure and childhood brain tumors. Furthermore, it appears that maternal smoking accelerates lung cancer risk in offspring who become cigarette smokers. It is planned to systematically measure the uptake of environmental smoke by infants who are formula-fed rather than breast-fed and whose mothers or primary care takers are cigarette smokers. The following groups of infants (equal percentage of boys and girls) will be assayed. 1. Age 1 month , summer collection, smoking mothers 50 cases 2. " , " , nonsmoking family 56 controls 3. " , winter collection, smoking mothers 50 cases 4. " , " , nonsmoking family 56 controls 5. Age 3 months, summer collection, smoking mothers 50 cases 6. " , " , nonsmoking family 56 controls 7. " , winter collection, smoking mothers 50 cases 8. " , " , nonsmoking family 56 controls The saliva of all primary caretakers will be analyzed for cotinine to validate their smoking habits. Vital and environmental data will be obtained on each household. Urine from each infant will be analyzed for pH, nitrate, thiocyanate, nicotine-N'-oxide, nicotine, cotinine, N-nitrosoproline and creatinine. The uptake of smoke particulates will be calculated on the basis of nicotine and cotinine data, absorption of gas phase constituents by thiocyanate. Elevated urinary excretion of N-nitrosoproline would reflect the endogenous nitrosation potential of inhaled environmental pollutants. It is the overall goal of this study to document the correlation between smoking intensity of mothers and the uptake of environmental smoke pollutants by their infants and to document ensuing biochemical changes. Infants who are involuntarily exposed to tobacco smoke and who have similar diets are regarded to be the most promising group for documenting the uptake and effects of environmental smoke exposure.